SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc78c877a0347c3d92b1a627a70fb6d39d4dfafa0ef3f1d59f5f3712b669019a' 
  AND token = 'dX+Tlj2v5Eja4fGB2WBQBGqwopZchYtYmjgurWyiF2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00074

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}